Crushing apparatus

ABSTRACT

A crushing plant having a pair of elongated conveyors, one over the other, which extend forwardly and upwardly under crusher means located forwardly adjacent to an input station at the rear of the plant, to different elevated discharge zones at the front of the plant. The upper conveyor receives crushed material discharging from the crusher means, and the lower conveyor receives input material of final product size sorted out in a material receiving and classifying unit at the input station. The conveyors can be arranged to discharge onto spaced upper and lower screen and transporting decks on a second crushing plant located ahead of the first, and having conveyor means cooperating with said lower conveyor to provide a final product conveyor extending the full length of both plants.

United States Patent Quinn CRUSHING APPARATUS John N. Quinn, c/o Johnson Welding & Equipment Co., Inc., 2470 Pennsylvania Ave., Madison, Wis. 53704 Filed: Aug. 5, 1974 Appl. No.: 494,7[5

US. Cl. 241/76; 241/80; 24l/IOL7 Int. Cl. B02C 21/02; B07B l/78 Field of Search 24l/76. 80, 101.7

Inventor:

3,841,570 l0/i974 Quinn ..24l/10l.7X

Primary Exanflner-Roy Lake Assistant Examiner E. F. Desmond 51 Dec. 23, 1975 [57] ABSTRACT A crushing plant having a pair of elongated conveyors, one over the other, which extend forwardly and upwardly under crusher means located forwardly adjacent to an input station at the rear of the plant, to different elevated discharge zones at the front of the plant. The upper conveyor receives crushed material discharging from the crusher means, and the lower conveyor receives input material of final product size sorted out in a material receiving and classifying unit at the input station. The conveyors can be arranged to discharge onto spaced upper and lower screen and transporting decks on a second crushing plant located ahead of the first, and having conveyor means cooperating with said lower conveyor to provide a final product conveyor extending the full length of both plants.

15 Claims, 6 Drawing Figures U.S. Patent Dec. 23, 1975 Sheet 1 of5 3,927,839

US. Patent Dec. 23, 1975 Sheet 3 of5 3,927,839

WJUE U.S. Patent Dec. 23, 1975 Sheet4 of5 3,927,839

Pic- 1.

US. Patent Dec. 23, 1975 Sheet 5 of5 3,927,839

mm o a qd d wd Q qd qd o owd d d 0 0 0 0 00 ONO K CRUSI-IING APPARATUS This invention relates to crushing apparatus, and has more particular reference to plants in which gravel is crushed, graded and finally discharged from the plant at one or more delivery zones thereon.

Examples of crushing plants of the type herein concerned can be found in the copending application of John N. Quinn, U.S. Ser. No. 3l7,l5l, filed Dec. 2|, I972; and in Quinn U.S. Pat. No. 3,622,089.

It is the primary purpose of this invention to provide a crushing plant which features an unusual degree of simplicity yet functions to crush materials in a remarkably efficient way, with a minimum of handling of said materials.

More particularly this invention has as an object the provision of a crushing plant which can be operated either in conjunction with auxiliary crushing apparatus or entirely independently of any additional crushing apparatus.

With these observations and objectives in mind, the manner in which the invention achieves its purpose will be appreciated from the following description and the accompanying drawings, which exemplify the invention, it being understood that changes may be made in the specific apparatus disclosed herein without departing from the essentials of the invention set forth in the appended claims.

The accompanying drawings illustrate two complete examples of the embodiments of the invention constructed according to the best mode so far devised for the practical application of the principles thereof, and in which:

FIG. I is a side elevation of a crushing plant of this invention shown as the rear or receiving section of a plant comprising both rear and front crushing sections;

FIG. la is a side elevational view of the front crushing section;

FIG. 2 is an enlarged fragmentary side view, partially in elevation and partly in section, illustrating a portion of the rear section;

FIG. 3 is an enlarged fragmentary side view of the front section, shown partly in section and partly in elevation;

FIG. 4 is a cross sectional view taken on the plane of the line 4-4 in FIG. 2; and

FIG. 5 is a fragmentary view similar to FIG. 2, but illustrating a modified embodiment of the invention.

Referring now to the accompanying drawings, the numeral 5 generally designates the rear or primary section of an elongated crushing plant, here shown as also comprising a front or secondary section 6 forwardly adjacent to the primary section.

Materials to be crushed are loaded into a material receiving and classifying unit 7 at an input station on the back of the primary section 5. The material receiving and classifying unit is of the vibratory type having upper and lower screen decks 8 and 9, respectively; and it is supported by the frame 10 of the primary section chassis at an elevation above a pair of longitudinally adjacent gate structures II and 12 which in turn are located over an upper substantially narrow rejection conveyor 13 and a lower substantially wider retention conveyor 14.

Both conveyors are of the belt type, and the narrow upper conveyor 13 is centered over the wider lower conveyor 14.

The gate structures II and 12 are located over the front and rear portions of the upper conveyor 13, and the latter projects rearwardly a short distance beyond the rear of the lower conveyor I4. The gate and conveyor structures, which will be discussed in greater detail hereinafter, are similar to those disclosed in my aforesaid copending application Ser. No. 3 l 7,1 5 I and they make it possible for fines which pass through both screen decks, to be rejected when they are directed onto the upper conveyor 13, or retained as part of the final product material produced by the plant when they are directed onto the lower conveyor 14.

Mounted on the primary or rear section 5 in a crushing zone located directly ahead of the vibratory unit 7, is a crusher device 16. The crusher device has been illustrated by way of example as comprising a twin roll crusher, although jaw or other types of crushers can be employed if desired.

An engine I7 provides a source of power for the crusher device I6 and for the vibratory unit 7, and is operatively connected thereto in a conventional manner.

The chassis frame 10 extends forwardly beyond the engine 17 for only a short distance, and is there supported by sets of tandem wheels l8. Rear wheels I8 support the rear of the chassis frame, and are located under the rear portion of the vibratory unit 7.

According to this invention, the primary crushing section 5 is provided with a pair of elongated belt type conveyors l9 and 20. These conveyors extend longitudinally of the chassis frame 10 from which they are supported, and they are mounted one over the other with the conveyor 19 uppermost and spaced a slight distance above the lower conveyor 20.

The upper conveyor 19 is mounted on the frame I0 so as to extend forwardly and at an upward inclination under the crusher device 16. It extends rearwardly beyond the outlet 22 of the crusher device so as to receive crushed materials discharging therefrom, and it terminates at a location adjacent to the fore portion of the input zone at which the vibratory unit 7 is mounted. It will be noted, therefore, that the rear end of the upper conveyor 19 is positioned slightly forwardly of and at a lower level than the front end of the conveyor 14. The lower conveyor 20 extends rearwardly a slight distance beyond the rear end of the upper conveyor to terminate substantially directly under the forward end of conveyor 14.

The forward ends of the upper and lower conveyors l9 and 20 terminate at elevated discharge zones a distance forwardly of the front end of the chassis frame I0; and the front end of the upper conveyor extends a short distance forwardly beyond that of the lower conveyor.

Input materials to be processed are loaded into the vibratory unit 7 in any suitable fashion, and are received on the upper screen deck 8 thereof. Large size pieces of material are retained on the screen deck 8 and are vibrationally advanced in the forward direction thereby to a chute structure 24. The chute 24 directs these large size pieces of input material into the inlet 26 of the crusher device 16, for crushing, and the crushed material issuing from its outlet 22 drops onto the upper conveyor 19 to be carried to a high discharge zone at its front end.

Smaller pieces of input material loaded into the vibratory unit 7 pass through the mesh of the screen of deck 8 and drop onto the lower screen deck 9. The

mesh size of the lower screen deck is preferably selected to pass materials of final product size along with fines which can be defined as sand, dust and the like. All materials that pass through the mesh of screen deck 9 drop into a hopper 28 therebelow, the bottom of which is defined by the lower conveyor 14.

The gate structures ll and 12 are mounted in the hopper, and each gate structure comprises a pair of hinged upright plates 30 mounted to swing about axes 3l adjacent to opposite sides of the conveyor 13. The conveyor 13 is substantially narrower than the conveyor 14, so that when the two gate forming plates of either gate structure are swung to inner positions with their upper ends in engagement with one another, they form a roof over the upper conveyor to prevent material from dropping onto it, and they cooperate with the inwardly sloping side walls 32 of the hopper to direct material by-passing conveyor 13 onto the wider lower conveyor 14.

When the gate forming plates of either gate structure are swung outwardly to their outermost limits of motion, they direct material passing through screen deck 9 onto the upper conveyor 13. Of course, the plates can be placed in different positions of adjustment on their pivots to divide the amount of pass through materials between the two conveyors l3 and 14.

With this arrangement of front and rear gate structures H and 12, the fines can generally be separated from the input material over the rear gate structure 12 and directed thereby onto the upper conveyor 13. The conveyor 13 is so driven that its upper stretch travels rearwardly, so as to carry the fines to a discharge zone at the rear of the plant.

Most of the input material of final product size ordinarily drops through the screen decks at a location over the front gate structure 1 l. The plates of the front gate structure can then be set to bypass materials around the upper conveyor 13 and direct them onto the lower conveyor l4. Since the lower conveyor is driven to have its upper stretch travel in the forward direction, the input material of final product size thereon is carried off of the front of the conveyor and into a chute structure 34. The chute structure 34 is slanted downwardly and forwardly to discharge onto the rear or receiving end portion of the conveyor 20.

Input materials of larger than final product size which fail to pass through the lower screen 9 are vibrationally advanced forwardly thereby and into a chute structure 36. The chute structure 36 extends downwardly behind the crusher device 16 and has its discharge end arranged over the rear or receiving end portion of the conveyor 19. Such oversize material deposited on the conveyor [9 is carried upwardly and forwardly along with crushed material from the crusher device 16 to the aforesaid high level discharge zone at the front of primary crushing section 5.

From the description thus far, it will be evident that the primary crushing section can be considered as a complete crushing plant capable of delivering product of two different sizes at the forward ends of conveyors l9 and 20. Also, if the fines are to be kept and mixed with the product of smaller size carried by the conveyor 20, the rear gates 12 can be closed over conveyor 13 to allow the fines to fall onto the forwardly driven conveyor 14.

As shown, however, the crushing plant can also be comprised of a front or secondary crushing section 6 which can be similar to some of those disclosed in my aforesaid copending application Ser. No. 317,151. For example, the front section 6 also comprises a chassis having front and rear wheels 41 and 42, respectively, and a frame 43 having a dropped center portion 44.

A drum type elevator 46 is carried by the frame 43 at said dropped center portion for rotation on a longitudinal axis. The elevator drum is located forwardly adjacent to a vibratory receiving unit 48 and rearwardly adjacent to a secondary crusher device 50 of any suitable type.

As shown, the materials discharging from the upper conveyor 19 on the primary section 5 drop onto a screen desk 52 in the upper portion of the vibratory unit 48. Some of these materials will pass through the mesh of the screen deck 52, but most will be advanced as carryover materials and discharged into the receiv ing end of a conveyor 54. The conveyor 54 can also be of the belt type and it extends upwardly and forwardly from the front of the vibratory unit 48, through the interior of the drum elevator, to the inlet 56 of the secondary crusher device 50.

The crushed materials issuing from the outlet 57 of the crusher device 50 fall onto the screen 58 ofa vibratory shaker unit 59 located under the crusher device, and pieces of final product size will pass through the screen to fall onto an elongated conveyor 60 below the shaker unit. Any pieces of material which are larger than final product size, however, will be vibrationally carried rearwardly on the screen of the shaker unit and into the lower interior portion of the elevator 46, for recirculation back to the crusher device 50 via conveyor 54.

Materials of final product size which pass through the mesh of screen deck 52 on the vibratory unit 48 fall through a hopper 62 therebeneath onto the upper forwardly driven stretch of a belt conveyor 64 at the bottom of the hopper for transfer to the conveyor 60. Conveyor 64 extends fore and aft the full length of the vibratory unit 48, and its rear end projects a short distance beyond the back of the unit to receive materials discharging from the forward end of conveyor 20 on the primary crushing section.

Hence, the final product size material from the conveyor 20, along with other final product size materials passing through the screens 52 and 58 are deposited on conveyor 60 to be carried forwardly and upwardly thereby to a high level discharge zone at the front of the secondary crushing section 6. it should be observed, however, that a downwardly and forwardly inclined chute 66 is mounted at the front of conveyor 64 to facilitate transfer of materials therefrom to the rear portion of conveyor 60.

It will also be observed that the three lengthwise adjacent conveyors 20, 64 and 60 in effect provide what amounts to a single continuous delivery conveyor extending for the combined lengths of the plant provided by the two crushing sections.

FIG. 5 illustrates a modification of the primary crushing apparatus having substantially the same vibratory receiving and classifying unit 7 and upper and lower conveyors l3 and I4 thereunder, and superimposed conveyors l9 and 20 which extend under the crushing station. However, the crusher means here comprises first and second stage crushers 70 and 71, respectively. If desired, the first and second stage crushers can comprise a double jaw type crusher, as shown.

The apparatus illustrated in FIG. 5 also differs from that previously described in that the upper screen deck 8 of vibratory unit 7 discharges carryover material along a chute-like extension 73 and forwardly over the mouth of the secondary crusher 71, into the mouth of the primary crusher 70. The lower screen deck 9, in this case, advances carryover material into the mouth of the secondary crusher 71, across a flap gate 75 forming the bottom ofa chute structure 76. The flap gate 75 forms the bottom of the chute structure 76 until it is swung from its horizontal position shown, to a downwardly depending position illustrated by broken lines. Carryover material then passing forwardly off of the forward end of the lower screen deck 9 can be made to bypass the crushers and instead flow onto the rear end portion of the lower conveyor 20.

Upper and lower chute structures 77 and 78, respectively, then cooperate to deliver such bypassed material to the conveyor 20. The lower chute structure 78 is on the order of the chute 34 in the first described embodiment of the invention. It has an open top, and it is mounted in front of the lower conveyor 14 to direct materials discharging .om its forward end onto the rear of conveyor 20.

The upper chute structure 77 is comprised of two branches. A vertical branch 80 leads downwardly beneath the flap gate 75 to a product delivery outlet 81 which opens to one side of the apparatus. The upper chute structure also comprises a rearwardly directed branch 82 which is effective to direct materials into the mouth of chute 78 at times when a gate 83 forming one bottom wall portion of said rearwardly directed branch is swung forwardly to its position seen in solid lines. When swung to its broken line upright position, gate 83 closes off the mouth of chute branch 82 and permits materials entering the upper end of branch 80 to discharge to the product delivery outlet 81.

By this arrangement, carryover material on the lower screen deck 9 of the vibratory unit 7 can be caused to discharge onto the rear of conveyor 20, along with final product material carried forwardly on conveyor l4 to chute 78. Alternatively, the carryover material on screen deck 9 can be fed into the mouth of the second stage 71 of the jaw crusher, which then discharges the crushed material directly onto the rear portion of the lower conveyor 20.

The first stage 70 of the jaw crusher receives the carryover material from the upper screen deck 8, and it discharges crushed material directly onto the rear portion of the upper conveyor 19.

The upper and lower conveyors l9 and can again deliver final product of two different grades; or they can discharge into a receiving and classifying unit such as that described earlier, or into one having upper and lower screen decks such as indicated.

Alternatively. the upper conveyor 19 can discharge into a chute 85 which extends laterally to one side of the apparatus and discharges onto the front end of an elongated belt conveyor 86. Chute 85 and conveyor 86 can be of the portable type, and the conveyor extends upwardly and rearwardly to discharge materials thereon into a chute 87. The chute 87 is sloped laterally inwardly toward the vibratory unit 7, so as to discharge onto the upper screen deck 8 to the latter.

In this way, oversize materials issuing from the first stage of the jaw crusher can be recirculated to the input station. If such material is then sized to pass through the upper screen 8 but not the lower screen 9. it will be retained on the lower screen and fed into the second stage of the jaw crusher providing the flap gate is in its horizontal position.

From the foregoing description, together with the accompanying drawings, it will be apparent to those skilled in the art that this invention provides crushing apparatus which features simplicity of construction and minimal handling of the materials processed therein.

Those skilled in the art will appreciate that the invention can be embodied in forms other than as herein disclosed for purposes of illustration.

I claim:

1. Elongated crushing apparatus having at its rear a vibratory receiving and classifying unit for input materials, and having a crushing station forwardly of said receiving and classifying unit, characterized by:

A. a pair of elongated conveyors mounted one over the other and extending forwardly and upwardly beyond said crushing station;

B. means comprising crusher means at said station, for depositing crushed materials onto the upper one of said conveyors for delivery thereby to a high load discharge zone at the front of the apparatus;

C. said lower conveyor having a receiving end located rearwardly of the rear of the upper conveyor;

D. screen means on said vibratory unit at a plurality of levels comprising a first screen member for vibrationally conducting input materials of large size forwardly into said crusher means, and a second screen member beneath said first screen member;

E. means beneath said second screen member for conducting final product size materials that pass therethrough to the receiving end of said lower conveyor;

F. and means for conducting carryover materials from the forward end of said second screen member to the rear portion of the upper conveyor in bypass relation to the crusher means.

2. The crushing apparatus of claim I, further characterized by:

A. said final product conducting means comprising a chute structure having its discharge end disposed over the receiving end of the lower conveyor;

8. and means for collecting and conducting to said chute structure said materials which pass through the mesh of said second screen member.

3. The crushing apparatus of claim 2, wherein said last named means comprises another conveyor, positioned beneath said second screen member to collect the material passing therethrough and discharge the same into said chute structure.

4. The crushing apparatus of claim 2, further characterized by chute means for conducting carryover materials from the forward end of said second screen member to said portion of the upper conveyor.

5. The crushing apparatus of claim 1, wherein said crusher means comprises first and second crushers; said first crusher receiving forwardly advanced carryover material from said first screen member and depositing materials crushed thereby onto the upper one of said conveyors; and said second crusher receiving forwardly advanced carryover materials from said second screen member and depositing materials crushed thereby onto the receiving end of the lower conveyor.

6. The crushing apparatus of claim 1, further characterized by:

A. an elongated material processing apparatus adjacent to the forward end of said crushing apparatus;

B. a vibratory receiving and classifying unit on said processing apparatus comprising a screen deck at an upper level onto which said upper conveyor discharges, to vibrationally advance carryover materials thereon forwardly for further processing;

C. means on said processing apparatus mounted under said screen deck to receive materials that pass therethrough together with materials that discharge from the forward end of said lower conveyor and to conduct such materials forwardly to a discharge zone;

D. and a delivery conveyor on said processing apparatus, to receive materials from said discharge zone and to conduct the same to a delivery zone.

7. The crushing apparatus of claim 1, further characterized by other crusher means having an inlet arranged to receive carryover material from the forward end of said second screen member, and having an outlet arranged to discharge crushed materials onto the receiving end of said lower conveyor.

8. The crushing apparatus of claim 7, further characterized by gate and chute means for diverting carryover material from the forward end of said second screen member to the receiving end of the lower conveyor, in bypass relation to the inlet of said other crusher means.

9. The crushing apparatus of claim 7, further characterized by gate and chute means for diverting carryover material from the forward end of said second screen member to either the receiving end of the lower conveyor or to a product delivery outlet adjacent to the crushing station.

10. The crushing apparatus of claim 1, further characterized by:

A. an elongated second crushing apparatus ahead of said first designated crushing apparatus and having secondary crusher means thereon;

B. conveyor means on said second apparatus to conduct materials discharged from the upper one of said conveyors to said secondary crusher means;

C. an elongated vibratory screen device located under said secondary crusher means to receive crushed materials issuing therefrom and adapted to allow materials of final product size to pass therethrough and to vibrationally advance carryover materials thereon toward and off one end of said screen device;

D. elevator means to receive the materials discharging from said one end of said screen device and to deposit the same on said conveyor means for recirculation back to the secondary crusher means;

E. and delivery conveyor means under said screen device to receive materials that pass therethrough and to conduct the same to a delivery zone at one end of said second crushing apparatus.

ll. Elongated crushing apparatus having at its rear a vibratory receiving and classifying unit for input materials, and having a crushing station forwardly of said receiving and classifying unit, characterized by:

A. a pair of elongated conveyors mounted one over the other and extending forwardly and upwardly beyond said crushing station;

B. means comprising crusher means at said station, for depositing crushed materials onto the upper one of said conveyors for delivery thereby to a high load discharge zone at the front of the apparatus;

C. said lower conveyor having a receiving end located rearwardly of the rear of the upper conveyor;

D. screen means on said vibratory unit at a plurality of levels comprising a first screen member for vibrationally conducting input materials of large size forwardly into said crusher means, and a second screen member beneath said first screen member;

E. means beneath said second screen member for conducting final product size materials that pass therethrough to the receiving end of said lower conveyor;

F. said crusher means being mounted on the plant at a location directly ahead of said vibratory unit, and having a single outlet from which crushed materials issue;

G. and an upright chute structure mounted on the apparatus at a location between the crusher means and said vibratory unit, for conducting to said portion of the upper conveyor carryover materials discharging from the forward end of said second screen member, in bypass relation to the crusher means.

12. An elongated crushing plant comprising adjacent front and rear sections each having crushing means thereon, characterized by:

A. means defining a delivery conveyor for material of final product size, said delivery conveyor being adapted to conduct final product size material forwardly from said rear section to the forward end of the front section;

8. screen means on the plant for passing and thereby separating final product size materials at three zones spaced from one another along the length of the plant, and for depositing said final product size materials onto the delivery conveyor;

C. the rearmost of said screen means comprising upper and lower screen decks of a vibratory material receiving and classifying unit located at an input station on the rear section;

D. the forward one of said screen members being located under the crushing means on said front section;

E. the third one of said screen members being located on the rear of said front section;

F. means for conducting carryover material on the upper screen deck of the rear section into the crushing means thereon;

G. a forwardly extending conveyor on the rear section between the crushing means thereon and the delivery conveyor, for conducting crushed material from said rear section crushing means upwardly and forwardly onto said third screen member;

H. means for conducting carryover material on said third screen member forwardly to the crushing means on said front section;

I. and means for conducting carryover materials from the forward end of said lower screen deck at the input station to the rear portion of said forwardly extending conveyor on the rear section in bypass relation to the crushing means on the rear section.

13. Elongated crushing apparatus having an input station at its rear and having crusher means at a location between said input station and the front of the apparatus, characterized by:

A. spaced apart elongated upper and lower conveyors extending forwardly and upwardly from a location forwardly adjacent to the input station, to delivery zones at different elevations at the front of the apparatus,

I. said upper conveyor being located to receive crushed materials issuing from said crusher means,

2. and the lower conveyor having its receiving end rearwardly of the upper conveyor;

B. a material receiving and classifying unit at the input station having upper and lower vibratory screens thereon for separating from the input material the two largest sizes thereof and for conducting the largest from the upper screen into the crusher means;

C. means for conducting the second largest size pieces of material from said lower screen onto the rear portion of the upper conveyor in bypass relation to said crusher means;

D. and conveyor means to receive final product size materials that pass through said screens and to conduct such final product size material onto the receiving end of the lower conveyor.

14. The crushing apparatus of claim 13, wherein said crusher means has a single outlet through which crushed materials issue to drop onto said upper conveyor.

15. Elongated crushing apparatus having at its rear a vibratory receiving and classifying unit for input materials and having crusher means forwardly adjacent to said vibratory unit, characterized by the following:

A. an elongated upper conveyor to carry materials crushed by said crusher means forwardly and upwardly to a first high level discharge zone at the front of the apparatus;

B. an elongated lower conveyor under and spaced from the upper conveyor and extending upwardly and forwardly to a second high level discharge zone at the front of the apparatus, said lower conveyor having a receiving end located rearwardly of the rear of the upper conveyor;

C. screen means on said vibratory unit at a plurality D. means beneath said lower screen member for conducting final product size materials that pass therethrough to the receiving end of said lower conveyor;

E. and means for conducting carryover materials from the forward end of said lower screen member to the rear portion of the upper conveyor in bypass relation to said crusher means. i I l 1 

1. Elongated crushing apparatus having at its rear a vibratory receiving and classifying unit for input materials, and having a crushing station forwardly of said receiving and classifying unit, characterized by: A. a pair of elongated conveyors mounted one over the other and extending forwardly and upwardly beyond said crushing station; B. means comprising crusher means at said station, for depositing crushed materials onto the upper one of said conveyors for delivery thereby to a high load discharge zone at the front of the apparatus; C. said lower conveyor having a receiving end located rearwardly of the rear of the upper conveyor; D. screen means on said vibratory unit at a plurality of levels comprising a first screen member for vibrationally conducting input materials of large size forwardly into said crusher means, and a second screen member beneath said first screen member; E. means beneath said second screen member for conducting final product size materials that pass therethrough to the receiving end of said lower conveyor; F. and means for conducting carryover materials from the forward end of said second screen member to the rear portion of the upper conveyor in bypass relation to the crusher means.
 1. said upper conveyor being located to receive crushed materials issuing from said crusher means,
 2. The crushing apparatus of claim 1, further characterized by: A. said final product conducting means comprising a chute structure having its discharge end disposed over the receiving end of the lower conveyor; B. and means for collecting and conducting to said chute structure said materials which pass through the mesh of said second screen member.
 2. and the lower conveyor having its receiving end rearwardly of the upper convEyor; B. a material receiving and classifying unit at the input station having upper and lower vibratory screens thereon for separating from the input material the two largest sizes thereof and for conducting the largest from the upper screen into the crusher means; C. means for conducting the second largest size pieces of material from said lower screen onto the rear portion of the upper conveyor in bypass relation to said crusher means; D. and conveyor means to receive final product size materials that pass through said screens and to conduct such final product size material onto the receiving end of the lower conveyor.
 3. The crushing apparatus of claim 2, wherein said last named means comprises another conveyor, positioned beneath said second screen member to collect the material passing therethrough and discharge the same into said chute structure.
 4. The crushing apparatus of claim 2, further characterized by chute means for conducting carryover materials from the forward end of said second screen member to said portion of the upper conveyor.
 5. The crushing apparatus of claim 1, wherein said crusher means comprises first and second crushers; said first crusher receiving forwardly advanced carryover material from said first screen member and depositing materials crushed thereby onto the upper one of said conveyors; and said second crusher receiving forwardly advanced carryover materials from said second screen member and depositing materials crushed thereby onto the receiving end of the lower conveyor.
 6. The crushing apparatus of claim 1, further characterized by: A. an elongated material processing apparatus adjacent to the forward end of said crushing apparatus; B. a vibratory receiving and classifying unit on said processing apparatus comprising a screen deck at an upper level onto which said upper conveyor discharges, to vibrationally advance carryover materials thereon forwardly for further processing; C. means on said processing apparatus mounted under said screen deck to receive materials that pass therethrough together with materials that discharge from the forward end of said lower conveyor and to conduct such materials forwardly to a discharge zone; D. and a delivery conveyor on said processing apparatus, to receive materials from said discharge zone and to conduct the same to a delivery zone.
 7. The crushing apparatus of claim 1, further characterized by other crusher means having an inlet arranged to receive carryover material from the forward end of said second screen member, and having an outlet arranged to discharge crushed materials onto the receiving end of said lower conveyor.
 8. The crushing apparatus of claim 7, further characterized by gate and chute means for diverting carryover material from the forward end of said second screen member to the receiving end of the lower conveyor, in bypass relation to the inlet of said other crusher means.
 9. The crushing apparatus of claim 7, further characterized by gate and chute means for diverting carryover material from the forward end of said second screen member to either the receiving end of the lower conveyor or to a product delivery outlet adjacent to the crushing station.
 10. The crushing apparatus of claim 1, further characterized by: A. an elongated second crushing apparatus ahead of said first designated crushing apparatus and having secondary crusher means thereon; B. conveyor means on said second apparatus to conduct materials discharged from the upper one of said conveyors to said secondary crusher means; C. an elongated vibratory screen device located under said secondary crusher means to receive crushed materials issuing therefrom and adapted to allow materials of final product size to pass therethrough and to vibrationally advance carryover materials thereon toward and off one end of said screen device; D. elevator means to receive the materials discharging from said one end of said screen device and to deposit the same on said conveyor means for recirculation back to the secondary crusher means; E. and delivery conveyor means under said screen device to receive materials that pass therethrough and to conducT the same to a delivery zone at one end of said second crushing apparatus.
 11. Elongated crushing apparatus having at its rear a vibratory receiving and classifying unit for input materials, and having a crushing station forwardly of said receiving and classifying unit, characterized by: A. a pair of elongated conveyors mounted one over the other and extending forwardly and upwardly beyond said crushing station; B. means comprising crusher means at said station, for depositing crushed materials onto the upper one of said conveyors for delivery thereby to a high load discharge zone at the front of the apparatus; C. said lower conveyor having a receiving end located rearwardly of the rear of the upper conveyor; D. screen means on said vibratory unit at a plurality of levels comprising a first screen member for vibrationally conducting input materials of large size forwardly into said crusher means, and a second screen member beneath said first screen member; E. means beneath said second screen member for conducting final product size materials that pass therethrough to the receiving end of said lower conveyor; F. said crusher means being mounted on the plant at a location directly ahead of said vibratory unit, and having a single outlet from which crushed materials issue; G. and an upright chute structure mounted on the apparatus at a location between the crusher means and said vibratory unit, for conducting to said portion of the upper conveyor carryover materials discharging from the forward end of said second screen member, in bypass relation to the crusher means.
 12. An elongated crushing plant comprising adjacent front and rear sections each having crushing means thereon, characterized by: A. means defining a delivery conveyor for material of final product size, said delivery conveyor being adapted to conduct final product size material forwardly from said rear section to the forward end of the front section; B. screen means on the plant for passing and thereby separating final product size materials at three zones spaced from one another along the length of the plant, and for depositing said final product size materials onto the delivery conveyor; C. the rearmost of said screen means comprising upper and lower screen decks of a vibratory material receiving and classifying unit located at an input station on the rear section; D. the forward one of said screen members being located under the crushing means on said front section; E. the third one of said screen members being located on the rear of said front section; F. means for conducting carryover material on the upper screen deck of the rear section into the crushing means thereon; G. a forwardly extending conveyor on the rear section between the crushing means thereon and the delivery conveyor, for conducting crushed material from said rear section crushing means upwardly and forwardly onto said third screen member; H. means for conducting carryover material on said third screen member forwardly to the crushing means on said front section; I. and means for conducting carryover materials from the forward end of said lower screen deck at the input station to the rear portion of said forwardly extending conveyor on the rear section in bypass relation to the crushing means on the rear section.
 13. Elongated crushing apparatus having an input station at its rear and having crusher means at a location between said input station and the front of the apparatus, characterized by: A. spaced apart elongated upper and lower conveyors extending forwardly and upwardly from a location forwardly adjacent to the input station, to delivery zones at different elevations at the front of the apparatus,
 1. said upper conveyor being located to receive crushed materials issuing from said crusher means,
 2. and the lower conveyor having its receiving end rearwardly of the upper convEyor; B. a material receiving and classifying unit at the input station having upper and lower vibratory screens thereon for separating from the input material the two largest sizes thereof and for conducting the largest from the upper screen into the crusher means; C. means for conducting the second largest size pieces of material from said lower screen onto the rear portion of the upper conveyor in bypass relation to said crusher means; D. and conveyor means to receive final product size materials that pass through said screens and to conduct such final product size material onto the receiving end of the lower conveyor.
 14. The crushing apparatus of claim 13, wherein said crusher means has a single outlet through which crushed materials issue to drop onto said upper conveyor.
 15. Elongated crushing apparatus having at its rear a vibratory receiving and classifying unit for input materials and having crusher means forwardly adjacent to said vibratory unit, characterized by the following: A. an elongated upper conveyor to carry materials crushed by said crusher means forwardly and upwardly to a first high level discharge zone at the front of the apparatus; B. an elongated lower conveyor under and spaced from the upper conveyor and extending upwardly and forwardly to a second high level discharge zone at the front of the apparatus, said lower conveyor having a receiving end located rearwardly of the rear of the upper conveyor; C. screen means on said vibratory unit at a plurality of levels comprising an upper screen member for vibrationally advancing oversize input materials forwardly into said crusher means, and a lower screen member which allows materials of final product size to pass therethrough; D. means beneath said lower screen member for conducting final product size materials that pass therethrough to the receiving end of said lower conveyor; E. and means for conducting carryover materials from the forward end of said lower screen member to the rear portion of the upper conveyor in bypass relation to said crusher means. 